Stents are implanted permanently or temporarily in patients to treat a variety of medical conditions. Prior to implantation, stents are often radially collapsed or crimped to a small diameter to allow the stent to be delivered through small passageways, such as a blood vessel or other anatomical lumen. Stents are crimped onto and delivered using a catheter. After the stent reaches the location to be treated in the patient, the stent is expanded or allowed to expand.
Crimping of the stent may result in damage. Tools used to crimp stents can be set or preprogrammed to crimp the stent to a preselected diameter, or can be set or preprogrammed to apply a maximum force. The stent may still be over-crimped even when the stent crimping tool is properly set or programmed. Over-crimping refers to crimping of a particular stent to a diameter that is smaller than what is desired for that stent. Over-crimping can impose undue strain on the struts of the stent. Excessive strain may lead to cracking of stent struts during stent crimping or expansion, or may otherwise affect the ability of the stent to expand. Because stents can be extremely small and intricate, even the slightest variation in crimping can have an adverse effect. Polymeric stents can be particularly sensitive to over-crimping, although metal stents can also be affected by over-crimping.
Over-crimping can be the result of one or a combination of factors, including mechanical variations in the stent crimping tool, variances (such as material thickness variances) in the production of the stent and/or catheter, and environmental conditions that effect the physical condition of the stent crimping tool, stent and/or catheter.
Accordingly, there is a need for a stent crimping tool insert, system, and method that prevents over-crimping.